Burglar-alarm



S. STEWART.

Burglar Alarm.

Patented Aug. 9. 1859.

JZtZ1-u66566 UNITED STATES PATENT OFFICE.

STEPHEN STEWART, OF PHILADELPHIA, PENNSYLVANIA.

BURGLAB-ALARM.

Specification of Letters Patent No. 25,057, dated August 9, 1859;

T 0 all whom it may concern:

Be it known that I, STEPHEN STEWART, of the city of Philadelphia, in the State of Pennsylvania, have invented a new and Improved Burglar-Alarm; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and the letters of reference marked thereon, in which- Figure 1 is a perspective View, and Fig. 2 is a longitudinal, perpendicular section.

A, is a box, of which one end is a hollow chamber open at one end, and having its sides extended as shown at C, forming guides.

B is an air chamber, air tight, except at the open end, which receives the piston D.

E is the piston rod connecting D with the cross head F and having notches in its upper side.

G is a gum spring fast at one end to the back end of box A, and at the other to the cross head F. There is a similar spring on the other side of the box A.

H is a lever moving freely on a fulcrum on the upper side of box A.

J, is a trigger sliding through slots in the guides O.

K is a common organ pipe or whistle set into the top of the box A, communicating with the air chamber B, in the usual manner.

M is a handle to cross head F.

N, is a steel spring keeping lever H, always bearing against under side of trigger J.

L, points at the four corners of box A,

which serve to hold it firmly to the floor when set for use.

The operation of the alarm is as follows: Upon retiring for the night the alarm is set by drawing the piston out by the handle M, until the lower end of lever H, drops into one of the notches on the upper side of the piston rod E and holds it fast. The box A is then pressed firmly on the floor so near the door that the end of trigger J, touches the door, and so hard on the floor that the points L, are forced into it and hold it fast. It follows then, that the moment the door is opened (if only a half inch) it will press against the trigger J, which instantly trips the lever H, liberates the cross head F, and piston D, when the gum springs G, at once exert their power upon the piston D, forcing it into the air chamber ,B, driving the air from B, through the whistle K, which immediately produces a shriek, arousing the sleeper, and informing the burglar at the door that he is detected.

I do not claim any one part of the above described alarm as being new, nor do I confine myself to any particular shape or material in constructing it. But

I do claim and desire to secure by Letters Patent The combination of the several parts A, B, C, D, E, F, G, H, J, K, L, M, N, and O,

as described and arranged to operate sub- 

